First of all, let me say how happy I am you did this. ^^ The story is very nice, though I had heard it before long ago as a child, but didn't exactly remember how it went. And I was very surprised at how much I could understand of it.

I'm glad you put the kanji version because I had to resource to it a few times when I got confused with the hiragana.

So, thank you.

And here is some things I saw I thought would be translated differently.

Konstantin wrote:「あれ？わたしのうちがありません」「あれ？私のうちがありません」“There? My house is not there.” – said Taro.

「あれ？」 is a interjection in this case I think. So would be something like "Eh?", "What?". And, though this is just a more personal opinion, wouldn't "here" be better instead of "there"? Since Tarou should probably be at the place is house was by then in the story... I just thought it looked a bit strange like that.

「はこのなかはなに？」「箱の中は何？」“What was inside the box?”

And here should be "What's inside the box?", I think. Because it's a speech line right? He's talking to himself.

しろいものがでてきます。けむりです。もくもくもく・・・白いものが出てきます。煙です。もくもくもく・・・Something white came out of the box. It was white smoke. Muku-muku-muku …

It was smoke. (No color mentioned in that sentence.) Moku-moku-moku (mokumoku is a mimetic word for "clouds of smoke", so you might want to substitute something else like "puff puff puff" or "billow billow billow")

I think I have a book with this story somewhere in my bookcase, but I never read it. I thought it was strange, I want to know what Taro did at the end, after he turned old. I actually resent Otohime and the turtle for keeping him in the Dragon Palace for 300 years so that he didn't get to say goodbye to his mother. And for making him old - was that supposed to be a good gesture, for bringing him to the correct time? It didn't seem very nice. He saved that turtle and he might've had a good three years with them, but his poor mother...

I get really attached to even minor characters in stories, this one made me sad. Am I supposed to be sad?! That said, don't get me started on Hachiko's story. Maybe I'm thinking too hard.

Nice story, and thanks for posting it and especially in the different forms, kana, kanji and English. It's very helpful for those studying the language.

I have just one small problem with your English translation. You used past tense. But in Japanese it's mostly (apart from quoted speech) in present tense eg います、食べます、行きます、降ります など など、So why is the translation in past tense?

Probably just because narratives in English are almost always past tense. It sounds somewhat strange for an extended narrative like this to be done in present tense in English, but it doesn't sound odd at all in Japanese.